You can use Emacs for all of your text processing needs,
internet and social network interactions, hacking, coding,
managing to-do's and organizing your daily schedule, playing
Tetris, and many other awesome things. It can even provide you
with free psychotherapy and counseling using the built
in doctor. A vibrant community of hackers is
constantly writing new extensions, thanks to the power of the
Emacs Lisp environment.

GNU Emacs is Free Software, both free as in free
beer and free as in free speech. The original Emacs was written
by St. iGNUcius himself — Richard
Stallman.

Not only does it give the user
the four
essential freedoms, its architecture is built in such a way
that you have the power to mold it, change it and make it comply
to your computering needs.

Why use Emacs?

Emacs is a very powerful text processor,
giving you the power to manipulate documents quickly and
efficiently. You can easily move through and edit paragraphs,
sentences, words, and logical blocks; blaze through text using
powerful search tools; and easily edit thousands of lines at once
using regular expressions, keyboard macros and more.

Colorful text editor

Emacs can be customized in every conceivable way, including its
looks. You
can strip it
down, choose between dozens of easy to install themes
with M-x load-theme, or even create your own and
share it with your friends. Here are a couple of nice theme galleries:
Emacs Themes,
Emacs Theme Gallery.

Et tu, Programmer?

There are tools for every programming language out there. Lisp,
Ruby, Python, PHP, Java, Erlang, JavaScript, C, C++, Prolog,
Tcl, AWK, PostScript, Clojure, Scala, Perl, Haskell, Elixir all
of these languages and more are supported in Emacs. Because of
the powerful Lisp core, Emacs is easy to extend to add support
for new languages if the urge strikes you.

You get lots of features out of the box, including syntax
highlighting, automatic indentation, REPL support, debugging,
code browsing, version control integration and much more.

More!

Org mode helps
you to keep notes, maintain TODO lists, plan projects and author
documents. You can use your Org documents to create HTML
websites like this one or export to LaTeX, Beamer, OpenDocuments
and many other formats.

Tramp allows you to edit remote files without
leaving Emacs. You can seamlessly edit files on remote servers
via SSH or FTP, edit local files with su/sudo, and much more.

Use the built in IRC client ERC along
with BitlBee to connect to your favorite chat
services, or use the Jabber package to hop on any XMPP service.

Out of the box Emacs includes a mail client, web browser,
calendar, and games; you can even edit video and images inside
Emacs. There
are more than 2,000 packages for
Emacs, and more are written all the time. You can easily extend
your Emacs with new packages
from GNU
ELPA, MELPA
and Marmelade
repositories.

Installing Emacs

Emacs is easy to install on almost every operating system out
there. Officially supported systems include GNU/Linux,
Mac OS X, Microsoft Windows, GNU/Hurd, FreeBSD, NetBSD,
OpenBSD, and Solaris. You can check out Get Emacs for simple, direct
installation directions for your system, or
read the following instructions:

GNU/Linux

GNU Emacs is available on every major GNU/Linux
distribution. It's available out of the box on several of them,
and if it's not you can install it with your system's package
manager or download Emacs directly from GNU.

Mac OS X

Emacs is included in Mac OS X, so you can just use Terminal.app,
type emacs and you're ready to roll. It's an old
version though, and it's recommended that you use the latest stable
version. To get the latest and greatest features, there are community built
packages like Emacs For OS
X or Homebrew that are easy to install.

Windows

Download these alternative icons

Learn Emacs

"Mastering Emacs is not the goal, it's the path."
A happy Emacs user

It's not called the self-documenting real-time display
editor for nothing. Emacs includes a great tutorial to
teach you how to use Emacs while you're using
Emacs. Mind blown? This is just the beginning.

Once you've installed Emacs and started it up, you will be greeted
with a welcome screen. From here you can click on
the Emacs Tutorial link with your mouse.

Or if you're the keyboard type, you can
press Alt + X on your keyboard, which will take you
to the command mode in the lower screen of Emacs. Type in
help-with-tutorial and press Enter. You just
entered the first of many Emacs commands. You know the warm
fuzzies you just got? Get used to it, because there's more where
that came from.

This interactive tutorial will teach you the basics on how to
move around and edit text. It's just the tip of the iceberg, and
your quest has just begun.